Huqianjing 虎鈐經

Huqianjing 虎鈐經 "The classic of the tiger seal" is a military treatise written during the Northern Song period 北宋 (960-1126) by Xu Dong 許洞 (976-1015), courtesy name Dongfu 洞夫 or Yuanfu 淵夫, from Wujun 吳郡 (today's Suzhou 蘇州, Jiangsu). The book was finished in 1004. It has a length of 20 juan and includes 210 chapters, each of which deals with a distinct topic.

The Huqianjing included the concept that in war, three realms played an important part, firstly, the realm of man who planned war and battles; second, the earth which provides formidable territory to wage war on; and third, the realm of Heaven which is involved into war in the shape of the weather, as well as by the influence of stars and deities. Divination thus plays a specific part in warfare, according to the Huqianjing.

A general must be able to observe the enemy and use his troops in a way that the enemy is not able to find out what their opponent is planning to do. Metaphysically, Xu Dong explains that a general must always be able to identify chance (ji 吉 "luck") in dangers (xiong 凶 "inauspicious situations") and to see when danger is hidden in apparently advantageous situations. The movements of the troops had to be adapted to such changes in luck. A vital foundation for victory was the supply of sufficient food and excellent weapons, in other words, a functioning logistics system.

Xu Dong lists the most critical points in a series of conditions: The precondition of establishing an army was a content population; the prerequisite of all tactics was caring for sufficient food; the precondition of deploying an army was to make use of advantageous territory; the prerequisite for victory was to harmonise the troops; the precondition of successful defence was a sufficient stock of supplies; and the prerequisite of a strong army was the justified application of reward and punishment. A wise general seized all opportunities (duoshi 奪恃), like weather, geographical obstacles, or the army's fighting mood. He had to feign cowardice to lure the enemy into attack (xi xu 襲虛). And he had to use his strengths after a victorious battle to pursue the enemy, to trap, and to eradicate him. It was not always good, warns Xu Dong, to apply traditional methods, but a general had to be flexible and adapt his tactics to the actual conditions.

The oldest surviving print dates from the Ming period 明 (1368-1644). It was the source for the edition in the imperial series Siku quanshu 四庫全書.